Sheet separating and feeding device



Dec. 25, 1962 A. SCHWEBEL 0,3

SHEET SEPARATING AND FEEDING DEVICE Filed Aug. 13, 1958 4 Sheets-Sheet 1Dec. 25, 1962 A. SCHWEBEL 3,070,367

SHEET SEPARATING AND FEEDING DEVICE Filed Aug. 13, 1958 4 Sheets-Sheet 2.l'm/eman' 19001. F Jaw/054 9/ HMMW Dec. 25, 1962 A. SCHWEBEL 3,070,367

SHEET SEPARATING AND FEEDING DEVICE Filed Aug. 15, 1958 4 Sheets-Sheet 5Hp 04 F Jayme-0:1.

firraRWErs' Inventor:

Dec. 25, 1962 A. SCHWEBEL 3,070,367

SHEET SEPARATING AND FEEDING DEVICE Filed Aug. 13, 1958 4 Sheets-Sheet 4Inventor 1400.4; Jams/554 into the blowing nozzles. to the invention, issuch that the air, while moving the United States Patent SHEETSEPARATING AND FEEDING DEVICE Adolf Schwebel, Offenbach (Main), Germany,assignor to Mabeg Maschinenbau G.m.b.H., Offenbach (Main),

Germany Filed Aug. 13, 1958, Ser. No. 754,759 Claims priority,application Germany Nov. 9, 1957 7 Claims. (Cl. 271-26) This inventionrelates to pneumatic sheet feeding devices such as are used in printingand the like machines to separate the sheets from a pile and to feedthem singly and successively into the machine by means of suctionnozzles and in which, preferably, means are provided for blowing airsideways into the upper sheets of the pile, and other means forcontrolling the height of the pile surface while the sheets are beingfed into the machine.

The invention has for its main object the removal of a number ofdisadvantages which are present in the hitherto used feeding devices ofthe aforesaid type and to provide a pneumatic separating and feedingdevice which shall be of simple construction, automatic in operation andreliable in its function.

Another object of the invention is the provision of means for sosupporting and arranging the separating nozzles as to render themselfcontained in their operation by a novel way of air distribution, andthe elimination of the mechanical means which hitherto had to beresorted to for the raising and lowering of the airnozzles.

A further object of the invention rests in the provision In anotherdevice of the type to which the invention refers, the suction nozzlesare kept in contact with the pile by means of a spring and, when thesuction is started, take the sheet upward thereby tensioning the spring.As soon as the suction ceases, the tensioned spring causes the suctionnozzle to fling back onto the pile surface.

Still another device is known in which the up and down movements of asuction plunger is controlled by the subpressure so as to tension aspring which, after having attracted a sheet by the suction nozzle,returns the latter into its upper position. This device suffers thedisadvantage that the suction elfect of the airwhen the latter arrivesthro gh the suction plunger in the space above the same, is already"spent to a great extent owing to the continuous Withdrawal of air.Devices of this type, therefore, are very unreliable and can not be usedin, high efficiency printing machines.

of a device of the aforesaid type in which the air entering the suctionnozzle, instead of being sucked 01f again, is used to practically itswhole volume and in conjunction with the tension produced by the vacuumin the cylinder, to force the suction nozzle downward onto the pile ofsheets to be conveyed.- The means for attaining this object include-asuction port or conduit arranged close to the bottom of the suctioncylinder below a piston head therein and a communication between thecylinder and a hollow plunger to which the suction nozzle is fitted.

In accordance with a still further object of the invention, air blowingnozzles are provided which, similar to the suction nozzles, are carriedat the end of hollow plungers. These plungers are guided in pressurecylinders in which they are moved downwardly by air which is admittedinto the cylinders and through the plungers The arrangement, accordingplunger and the nozzle downwardly, accumulates in front of the jetopening in the nozzle through which it is'then forced by the pressure ofthe succeeding volumes of air.

The air issuing from the jets of the blowing nozzles blows'down alongthe pile between the uppermost sheets thereof, while preliminaryseparating brushes are provided to move up and down the edge of the pilein confromity with the blowing nozzle and in timed relation to theseparating and feeding means in order to facilitate the separation ofthe sheets.

Yetanother object of the invention rests in the provision of a tracerroll which also moves-in timed relation to the separating and feedingmeans to control theposition of the pile surface, and which closes acircuit for independently of the suction elfect. 3m 1 .and down movementof the nozzles is effected wholly A pneumatic separating and feedingdevice in accordance with the invention is diagramaticaly illustrated inthe accompanying drawings by way, of example. In these drawings: g Y vFI G. 1 shows a side elevation, partly in section, of the pneumaticseparating and feeding" mechanism.

' FIG. 2 is a part-sectional elevation of a separating and/ or feedingnozzle; FIG. 3 is a'view similar to FIG. 2 of a blowing nozzle. 1 FIG. 4illustrates a; front elevation of the pile end @1 ing switch, while i IFIG. 5 is' a detaili showing partof the said switch. FIG. 6 is aside'view, p'artly'in section, of the pile end closin'g switehinaccordance with'FIG. 4. f

F16 7 is a plane view of FIG. ion a reduced scale, and FIG. '8 a sectionthrough the air controlling means. Referring to FIG. 1, the pile tableis denoted by the numeral 1, on which ispositioned a pile 2 of sheets tobe separatedand fed into a machine such as a printing machine orthelike. The pile table 1 is suspended in substantially known manner onchains 3 at either side of the device. Arranged in front of the pile isthe feed 'roller' 4 and the guide or pressure roller 5 between'which asheet 8 after its separation from the pile by the nozzle 7 and after ithas been raised above the said pile is conveyedinto the machine. Thesheet separating and feeding means, comprising suction and blowingnozzles, farining brushes, positioning'abutr'nents, and other elementsas are'required for the separation of the sheets-from the 'pile, areformed into a self-contained aggregate'and slidably positioned above thepile on a shaft 9 so as to be capable of adjustment to any size ofsheets to be conveyed. "Positioned in front of the pile and in thevicinity of the feed roller 4, are abutment rails =10 and a movable stop11. The fanning brushes""1 2 can be moved together with their holders 13along a shaft-14 in accordance with the width of the sheets. They arepreferably arranged in pairs and so as to bearwith about the upperhalves of their bristled heads on the edge of the pile. They can beraised and lowered with their extended back 15 in the holders 13;abutment screws 16, or the likeybeing provided to limit their movementin both directions. A particular advantage of this arrangement rests inthat the brushes are thus capable of partaking in the receding or risingmovement of. the pile surface, so that no alterations in the conditionsfor an orderly separation of the topmost sheet from the pile can takeplace.

The separating and feeding means which separate the top sheets from thepile 2 by suction and feed them to the rollers '4 and 5, consist of thecylinders 6 and 7,

-Which are mounted, preferably in pairs, on the shafts 18 the cylinder 7in FIG. 2, is a hollow plunger 19 carrying at its lower end a nozzle 20of preferably resilient material such as rubber or the like. The saidnozzle is only pushed onto the plunger so it can be easily removed andreplaced by another nozzle of different type or shape. At its top theplunger 19 is provided with a piston head 21 adapted to slide in thecylinder 6 and to serve as a spring plate for a compression spring 22which tends to urge the plunger into its upper position. An orifice 25in the wall of the plunger permits communication of the interior 23 ofthe plunger with the chamber 24 of the cylinder. A cylinder cover 26provides an airtight closure of the cylinder during the withdrawal ofthe air from the chamber 24 via the conduit 27 at the lower end of thecylinder.

A control valve 50 (FIG. 8) of any known or convenient type and whichforms no part of the invention, permits of withdrawing the air from thecylinder chamber 24 through the suction conduit 27, whereas the airwhich enters the interior of the suction plunger 19 is not sucked offbut is allowed to move the plunger downwardly by pressing on the pistonhead 21 in conjunction with the full tension prevailing in the cylinder,until the top sheet of the pile is attracted by the nozzle, as at 8 inFIG. 1, whereby the nozzle 20 is closed.

In continuation of the process just described the air in the hollowplunger 19 and in the chamber above the piston head is also sucked ofi,whereby the tensional forces in the chambers are compensated and theplunger, with the top sheet adhering to it is lifted by the spring 22and thus returned into its initial position.

The cylinder 6 is of substantially the same construction as the cylinder7 just described, but its plunger 23a and nozzle 204 do not take part inthe separation but only in the feeding of the sheet. This is to say thatthe plunger. 23a in cylinder 6 is lowered by the air acting on itspiston head, such as 21, just a slight amount until it contacts with thesheet 8 after the same has been raised by the returning nozzle 20 asshown in FIG. 1. At this moment the air in the cylinder 7 is cut off sothat the sheet is supported by the nozzle 20a of the cylinder 6 only,which immediately is moved by the parallelogram levers 17 in thedirection of and between the feed roller 4, 5, after which the suctionair also in this cylinder 6 is cut off and the sheet 8 is carried on bythe rollers 4, into the printing or other mechanism of the machine,while the cylinder 6 itself is returned by the parallelogram 'levers 17into its initial position.

The aforedescribed action of separating and feeding the top sheet of thepile may be enhanced by the employment of blowing nozzles 32 which moveup and down in timed relation to the separating means in order to blowair in between the sheets at the top of the pile (FIGS. 1 and 3). Thearrangement of the blowing nozzles is similar to that of the suctionnozzles, consisting of a cylinder 28 in which a blowing plunger 29 ismovable in vertical direction and urged upwardly by a compression spring30. Air enters the cylinder via the socket 31 and leaves it by thenozzle 32 through the jet opening 32a which is of comparatively broadand narrow formation.

Compressed air is supplied to the blowing plunger 29 in timed relationto the operation of the suction means and accumulates at the lower endof the passage 33 in front of the jet 32a, whereby it acts in commonwith the air pressure on the piston head 34 to move the plunger 29, 32downwardly against the action of the spring 30 and, at the same time, toblow air in between the upper sheets of the pile, a vent hole 28a beingprovided to return accumulated air from the cylinder into theatmosphere. During the intervals in the admission of the air asregulated by the control valve 50, the plunger is returned into itsinitial position by the compression spring 30 in the cylinder.

It stands to reason that the wholly air-operated separating, feeding andblowing means 6, 7, and 28 are less subjected to wear than themechanically controlled means which have hitherto been employed. Theyare also most simple in construction and arrangement and require hardlyany attention to keep them in workable condition.

The suction air and the blowing air are released for distributionthrough the control valve 50 by means of a hand lever 55 operating adistribution valve 51 (FIG. 8). The correct timing for the actuation ofthe hand lever is controlled in substantially known manner by a cam 56aand cam lever 56 in timed relation to the feeding of the sheets from thepile. The air distribution valve 51 with its graduated scale (not shown)and the control valve 50, as also the regulatable suction and blowingair means 52, 53 are arranged directly adjacent their places of use sothat the air conduits 65 and 66 can be made very short, as shown in FIG.7, and disturbances caused by the hitherto usual length of the conduitseliminated.

The control valve 50 (FIGS. 7 and 8) substantially consists of acylinder 60 which rotates once for each sheet fed into the machine. Thecylinder 60 is provided with three ports 61, 62, and 63, which arecontrolled to connect, at their respective intervals, the separatingnozzles 7 by the port 61 from the socket 53 over the conduits 69, 70.The feed nozzles 6 from the socket 52 over the conduits 67, 68 by theport 62, and the blowing air nozzles 28 by the port 63 over the conduits65, 66.

The distributing valve 51 serves to admit the suction and the blowingair to the control valve 50 by the actuation of the valve plate 64through the hand lever 55. The said valve plate is locked and unlockedby the aforesaid cam 56a and the cam lever 56 in timed relation to thefeeding of the sheets, which ensures the hand lever to be absolutelyfool-proof and operable only when the separating nozzles are loweredinto contact with the surface of the pile.

It is necessary that the top sheet of the pile must maintain a certaindistance from the separating and feeding means and, in particular, fromtheir nozzles if the device is to operate free of disturbance. For thatreason certain lifting means operable in dependence of the pile surfaceare provided to function in conjunction with the sheet separating means.These lifting means, in accordance with the invention, are such as to becapable of being used as end switches, which is a further simplificationof the construction and in the manipulation of the device.

Referring to FIGS. 1, 4 and 5, a cam 36 is provided which acts on a bellcrank lever 37 to move the same together with the sheet separating andfeeding means 7 and 6 in timed relation to the feeding of the sheets,whereby a tracer roll 40 and its holder 39 are raised and lowered inrelation to the pile 2; the holder 39 being suspended from a lever 42and moved by the rocking shaft 41. If required by the kind of work orthe quality of the sheets, the tracer roll 40 may be adjusted somewhatlower as indicated at 43. Thumb levers 44 and 45 and a hand lever 38 arealso arranged upon the rocking shaft 41, as will presently be described.

If during the separation of the sheets the top surface of the pilerecedes, the tracer roll 40 with its holder 39 will follow, until itreaches the position 40a in FIG. 5. This causes an abutment 46 on theholder (FIGS. 4 and 6) to encounter the button of a switch 47 andthereby to close the circuit via the lines a and b to the lifting motor48 and the line 0 to the main. The chains 3 are now set in motion andlift the pile table 1 until its former posi tion is reestablished andthe abutment 46 moved out of contact with the switch button 47, whilethe switch 49 becomes interrupted. As soon as the table 1 has reassumedits normal position and the roller 40 reattained the position of FIG. 4,the switch 47 is cut out again and theswitch 49 closed over the wires :1and e, a to the motor 48 and back over the wire c to the main.

When the handle 38 is turned so that the thumb lever 44 shortcircuitsthe working circuit and the switch 49 and the tracer roll 40 is pressedinto the position 40a (FIG. 5) by the thumb lever 45 owing to the pin45a pressing on the lever 42, the tracer roll is in a position ofreadiness to be used as a limit switch.

The upward movement of the new pile for taking up its correct positionin relation to the separating means becomes interrupted when it strikesthe roll 40. The pile then returns into its initial position with thethumb levers 44, 45 and the hand lever 33, whereby the circuit to thelifting motor 48 and, therewith, the lift of the pile is againinterrupted at the switch 49.

The limit switch which has been in its position of rest, is not in aposition of working readiness as a means for controlling and tracing theposition of the top surface of the pile.

What I claim is:

1. In a pneumatic sheet separating and feeding device comprising incombination a platform supporting a pile of sheets to be fed insuccession; means for raising said platform so as to maintain the top ofsaid pile of sheets at a substantially constant level; a pair ofhorizontally arranged feeding rollers disposed adjacent the forward endof said pile of sheets; first suction means mounted for longitudinal andlateral adjustment above said pile of sheets near the rear end thereofsaid first suction means being movable in a vertical direction bydifferential pressure to engage, hold, and lift the top sheet of saidpile; vertically reciprocating blowing means movable in timedrelationship with the vertical movement of said first suction means bycompressed air downward past the rear edge of said pile of sheets forseparating the lower sheets from each other from said lifted top sheetmounted for longitudinal and lateral adjustment together with said firstsuction means; brushes mounted for longitudinal, vertical and lateraladjustment engaging the rear upper edge of said pile of sheets andsupporting sheets raised by said bowing means; second suction meansmounted for longitudinal and lateral adjustment above said pile ofsheets in spaced relation to said first suction means movable in avertical direction by differential pressure to engage and hold saidlifted and separated upper sheet and movable in a longitudinal directiontoward said pair of feeding rollers after said first suction means havereleased said uppermost sheet, means correlating the action of the firstand second suction means and the blowing means, and height-sensing meansfor said pile of sheets movable in synchronism with said first andsecond suction means for energizing said lifting means.

2. In a pneumatic sheet separating and feeding device comprising incombination a platform supporting a pile of sheets; means for liftingsaid platform so as to maintain the top of said pile of sheets at asubstantially constant level; a pair of feeding rollers disposed infront of said sheets; a central guide rail provided above said pile ofsheets extending in a horizontal, longitudinal direction over the entirelength of said platform; a slide member arranged for longitudinaladjustment on said central guide rail; a first supporting member mountedon said slide member and extending rectangularly and horizontally towardboth sides of said central guide rail across the entire width of saidplatform; first suction means mounted for lateral adjustment on saidfirst supporting member, said first suction means being movable in avertical direction by differential pressure and disposed to engage, holdand lift the rear end of the top sheet; vertically reciprocating blowingmeans mounted for lateral adjustment with said first suction means onsaid first supporting member, said blowing means being movable bycompressed air downward in timed relationship with the vertical movementof said first suction means past the rear edge of said pile of sheetsfor separating the lower sheets from each other and from said lifted topsheet; brushes mounted for lateral adjustment on said first supportingmember engaging the rear upper edge of said pile of sheets, holding themspread apart and facilitating the separation of said uppermost sheet; asecond supporting member spaced forwardly in parallel relation to saidfirst supporting member and extending over the entire width of saidplatform, said second supporting member being connected with saidlongitudinal slide member by a parallel linkage assembly for moving saidsecond supporting member in timed relation to the action of said firstsuc tion means; second suction means mounted for lateral adjustment onsaid second supporting member and being movable in a vertical directionby differential pressure to engage, hold and lift said separated uppersheet moving the latter in a longitudinal direction toward said pair offeeding rollers after said first suction means have released said sheet,means correlating the action of the first and second suction means andthe blowing means, and height-sensing means for said pile of sheetsmovable in synchronism with said first and second suction means forenergizing said lifting means.

3. In a pneumatic sheet separating and feeding device comprising incombination a platform supporting a pile of sheets to be fed insuccession; said platform being suspended on chains engaging sprocketsdrivably connected with an electric motor, a tracing roll engaging thetop of said pile of sheets being arranged at the free end of a bellcrank lever actuated by a cam to lift said tracing roll in timedrelation with the feeding of said sheets, cam means connected with saidbell crank lever adjacent said tracing roll closing a switch actuatingsaid motor to lift said platform when a predetermined lower level of thetop of said pile of sheets is attained and opening said switch fordeenergizing said motor when a predetermined level of the top of saidpile of sheets is reached, a pair of horizontally arranged feedingrollers disposed adjacent the forward end of said pile of sheets; firstsuction means mounted for longitudinal and lateral adjustment above saidpile of sheets near the rear end thereof, said first suction means beingmovable in a vertical direction by differential pressure to engage, holdand lift the top sheet of said pile; vertically reciprocating blowingmeans movable by compressed air downward in timed relationship with thever tical movement of said first suction means past the rear edge ofsaid pile of sheets for separating the lower sheets from each other andfrom said lifted top sheet; brushes mounted for longitudinal, verticaland lateral adjustment engaging the rear upper edge of said pile ofsheets and supporting sheets raised by said blowing means; secondsuction means mounted for longitudinal and lateral ad justment abovesaid pile of sheets in spaced relation to said first suction meansmovable in vertical direction by differential pressure to engage andhold said lifted and separated upper sheet and movable in a longitudinaldirection toward said pair of feeding rollers after said first suctionmeans have released said uppermost sheet, and means correlating theaction of the first and second suction means and the blowing means.

4. In a pneumatic sheet separating and feeding device comprising incombination a platform supporting a pile of sheets to be fed insuccession; said platform being suspended on chains engaging sprocketsdrivably connected with an electric motor; a tracing roll engaging thetop of said pile of sheets being arranged at the free end of a bellcrank lever actuated by a cam to lift said tracing roll in timedrelation with the feeding of said sheets; cam means connected with saidbell crank lever adjacent said tracing roll closing a switch actuatingsaid motor to lift said platform when -a predetermined lower level ofthe top of said pile of sheets is attained and opening said switch fordeenergizin-g said motor when a predetermined level of the top of saidpile of sheets is reached; a second switch provided to stop said motorlifting said platform when the original height of the pile has beenreattained; a hand lever provided for manually actuating means engagingand lowering said cam means connected with said bell crank lever so asto place said first switch in readiness to serve as a limit switch; apair of feeding rollers disposed in front of said sheets; a centralguide rail provided above said pile of sheets extending in horizontal,longitudinal direction over the entire length of said platform; a slidemember arranged for longitudinal adjustment on said central guide rail;a first supporting member mounted on said slide member and extendingrectangularly and horizontally toward both sides of said central guiderail across the entire width of said platform; first suction meansmounted for lateral adjustment on said first supporting member saidfirst suction means being movable in vertical direction by differentialpressure and disposed to engage, hold and lift the rear end of the topsheet; vertically reciprocating blowing means mounted for lateraladjustment with said first suction means on said first supportingmember, said blowing means being movable by compressed air in timedrelationship with said first suction means past the rear edge of saidpile of sheets for separating the lower sheets from each other and fromsaid lifted top sheet; brushes mounted for lateral adjustment on saidfirst supporting member engaging the rear upper edge of said pile ofsheets holding them spread apart and facilitating the separation of saiduppermost sheet; a second supporting member spaced forwardly in parallelrelation to said first supporting member and extending over the entirewidth of said platform, said second supporting member being connectedwith said longitudinal slide member by a parallel linkage assembly formoving said second supporting member and in timed relation to the actionof said first suction means; second suction means mounted for lateral oadjustment on said second supporting member and being movable invertical direction by differential pressure to engage, hold and liftsaid separated upper sheet moving the latter in longitudinal directiontoward said pair of feeding rollers after said first suction means havereleased said sheet.

5. A pneumatic sheet separating and feeding device according to claim 1in which said blowing devices each comprises a substantially verticallyarranged cylinder closed at both ends by plates, a piston slidablyarranged within said cylinder and urged upwardly by a compressionspring; a hollow piston rod open at both ends extending through saidpiston and the lower endplate of said cylinder and carrying on itsoutwardly extending end an arcuately shaped blowing nozzle communicatingthrough said hollow piston rod with the cylinder space above saidpiston, said blowing nozzle being provided with a narrow horizontallyextending jet opening; an inlet for compressed air provided at the upperend of said cylinder; and a vent hole provided in the lower end plate ofsaid cylinder, said compressed air the outlet of which being restrictedby said jet opening causing said piston to move downwardly against theaction of said spring.

6. A pneumatic sheet separating and feeding device according to claim 4,in which a control valve of any suitable type, such as rotatable valves,is arranged adjacent said suction and said blowing means connecting saidfirst and said second suction means with a source of negative airpressure and said blowing means with a source of positive air pressurein timed relation.

7. In a pneumatic sheet separating and feeding device comprising incombination a platform supporting a pile of sheets to be fed insuccession; means for raising said platform so as to maintain the top ofsaid pile of sheets at a substantially constant level; a pair ofhorizontally arranged feeding rollers disposed adjacent the forward endof said pile of sheets; first suction means mounted for longitudinal andlateral adjustment above said pile of sheets near the rear end thereof,said first suction means being movable in a vertical direction bydifferential pressure to engage, hold, and lift the top sheet of saidpile; vertically reciprocating blowing means movable by compressed airdownward past the rear edge of said pile of sheets for separating thelower sheets from said lifted top sheet mounted for longitudinal andlateral adjustment together with said first suction means; brushesmounted for longitudinal, vertical and lateral adjustment engaging therear upper edge of said pile of sheets and supporting sheets raised bysaid blowing means; second suction means mounted for longitudinal andlateral adjustment above said pile of sheets in spaced relation to saidfirst suction means movable in a vertical direction by differentialpressure to engage and hold said lifted and separated upper sheet andmovable in a longitudinal direction toward said pair of feeding rollersafter said first suction means have released said uppermost sheet, meanscorrelating the action of the first and second suction. means and theblowing means, height sensing means for said pile of sheets movable insynchronism with said first and second suction means for energizing saidrais ing means, said first and second suction means each comprise asubstantially vertically arranged cylinder closed at both ends by platesand being provided with a suction port at its lower end communicatingwith a suction line; a piston slidably arranged with said cylinder andurged upwardly by a compression spring; a hollow piston rod open at bothends extending through said piston and the lower end plate of saidcylinder and carrying on its outwardly extending end a suction cupcommunicating through said hollow piston rod with the cylinder.

References Cited in the file of this patent UNITED STATES PATENTS503,063 Orser Aug. 8, 1893 614,772 Siege] Nov. 22, 1898 1,480,012 RodenJan. 8, 1924 1,867,038 Upham July 12, 1932 2,140,023 McElroy et al Dec.13, 1938 2,144,057 Hallstream Jan. 17, 1939 2,183,077 Kast Dec. 12, 19392,247,473 Binder July 1, 1941 2,350,511 Lake et al June 6, 19442,714,006 Layden July 26, 1955 FOREIGN PATENTS 581,829 Great BritainOct. 25, 1946

